Will the Ocean Become a Cocktail to Save the Planet from Global Warming?

Author:  Phillips Veronica

Date:  October 2007

Recognizing global warming as a threat to life on Earth, scientists are trying to develop a method to alleviate or reverse its effects. Recently Nature published a letter to the editor that suggested how large vertical pipes can be used to mix the ocean's nutrient-rich deep waters and nutrient deficient surface waters in an effort to sequester the planet's excess of CO2 and to potentially cool the climate.

The authors of this letter, James Lovelock, father of the Gaia theory (which states that the Earth is capable of recovering from the environmental disturbances), and Chris Rapley, director of the London Science Museum, believe that this technology could act as an "emergency treatment for the pathology of global warming." In their letter they emphasize the point that using the Earth's own energy to help the planet heal itself at the risk of unwarranted side effects has no guarantee of success but is justified by the fact that the "stakes are so high."

The project would work by bringing nutrient-rich water from depth and allowing blooms of algae on the surface, which would consume CO2 through photosynthesis. Chemicals produced by the algae may contribute to cloud formation, which would reflect sunlight and reduce rising temperatures.

Scientists and policy-makers confer at Woods Hole Oceanographic Institution (WHOL) in Massachusetts to discuss the scientific and legal elements of this kind of project of ocean fertilization.

A system to absorb CO2 through ocean upwelling is already in development by Atmocean, a company based in Santa Fe, New Mexico. The wave-driven ocean upwelling system is comprised of 300 meter-long floating tubes 3 meters in diameter. Phil Kithil, chief executive officer of the company said that if their technology is deployed in 80% of the Earth's oceans, the ocean's annual rate of CO2 sequestration could be doubled.

However, scientists are in disagreement as to what kind of effect this technique would actually have on the CO2 budget, if any. Scott Doney, a marine chemist at WHOI, believes that the concept is flawed, pointing out that deep waters with high nutrient content also have high levels of dissolved inorganic carbon, and that bringing these waters to the surface will result in CO2 bubbling into the air. This could instead lead to a net gain of CO2. Ken Buesseler, another marine chemist at WHOI, argues that the ratio of CO2 removed as biomass from the surface to that which would be brought up from depth would stay constant. He also points out the potential for a negative impact on marine life.

The idea of using ocean circulation to reduce CO2 levels is not a new one. Other ideas for the mitigation of global warming include placing mirrors in space to reflect sunlight.

Author: Veronica Phillips

Reviewed by: Suvash Shrestha

Published by: Konrad Sawicki